Carpal tunnel syndrome

Carpal tunnel syndrome is a disorder caused by compression at the wrist of the median nerve supplying the hand, causing numbness and tingling. The carpaltunnel is an area in the wrist where the bones and ligaments create a small passageway for the median nerve. The median nerve is responsible for both sensation and movement in the hand, in particular the thumb and first three fingers. When the median nerve is compressed, it cannot function normally, and anindividual's hand will feel as if it has "gone to sleep."

Because the carpal tunnel is very narrow, any swelling or fluid accumulationin the area will lead to pressure on the median nerve. Pregnancy, obesity, arthritis, certain thyroid conditions, diabetes, and certain pituitary abnormalities may cause carpal tunnel syndrome. Various injuries to the arm and wrist(including fractures, sprains, and dislocations), can also increase the riskof carpal tunnel syndrome.

Jobs which require an individual to repeatedly bend the wrist inward toward the forearm are a leading cause of carpal tunnel syndrome. Injuries of this type are referred to as "repetitive motion" injuries, and are more frequent among secretaries doing a lot of typing, people working at computer keyboards orcash registers, factory workers, and some musicians. In 1995, about $270 million was spent on sick days taken for pain attributed to repetitive motion injuries.

Symptoms of carpal tunnel syndrome include numbness, burning, tingling, and aprickly pin-like sensation over the palm surface of the hand, and into the thumb, forefinger, middle finger, and half of the ring finger. Some individuals notice a shooting pain which goes from the wrist up the arm, or down into the hand and fingers. With continued median nerve compression, an individual may begin to experience muscle weakness, making it difficult to open jars andhold objects with the affected hand. Eventually, the muscles of the hand served by the median nerve may begin to grow noticeably smaller (atrophy), especially the fleshy part of the thumb. Untreated, carpal tunnel syndrome may eventually result in permanent weakness, loss of sensation, or even paralysis ofthe thumb and fingers of the affected hand.

To diagnose carpal tunnel syndrome, a doctor will perform a variety of simpletests to measure muscle strength and sensation in the affected hand and armof the patient. Wrist x rays are often taken to rule out the possibility of atumor pressing against the median nerve. Further testing may include electromyographic or nerve conduction velocity testing. These tests involve stimulating the median nerve with electricity and measuring the speed and strength ofthe muscle response and how fast the nerve transmission travels across the carpal tunnel.

Carpal tunnel syndrome is initially treated with splints, which support the wrist and prevent it from flexing inward. Some people get significant relief by wearing splints to sleep at night, while others will need to wear the splints all day, especially if they are performing jobs which stress the wrist. Ibuprofen or other nonsteroidal anti-inflammatory drugs may be prescribed to decrease pain and swelling. When carpal tunnel syndrome is advanced, injectionof steroids into the wrist to decrease inflammation may be necessary.

The most severe cases of carpal tunnel syndrome may require surgery. Local anesthesia (numbing medication) or nerve blocks (the injection of anesthetics directly into the nerve) are used to deaden the wrist area, and the ligament which crosses the wrist is cut to decrease compression of the median nerve. Recovery from this type of surgery is typically quick and carpal tunnel symptoms stop completely for about 95% of surgical patients.

Early use of a splint may be helpful for people whose jobs place them at riskof carpal tunnel syndrome. In addition, people who must work long hours at acomputer keyboard, can take advantage of recent advances in "ergonomics," which position the keyboard and computer components in a way that increases efficiency and decreases stress.

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